There have conventionally been proposed various ion generators that generate both positive and negative ions. For example, Patent Publication 1 listed below discloses an example in which such an ion generator is applied to a vehicle. Specifically, as shown in FIG. 12, inside the interior walls 101 and 102 that form the passenger space inside a vehicle, there is formed a passage 103 through which to feed air-conditioned air into the passenger. Inside this passage 103, an ion generator 104 is arranged, so that air containing the ions generated by the ion generator 104 is fed through wind direction control plates 105 into the passenger space inside the vehicle.    Patent Publication 1: J-P-A-2003-151718